Locating subterranean pipes is a necessity in view of costs incurred due to accidental damage thereto. For example, utility companies often damage subterranean pipes as a result of trenching procedures, etc. Although most subterranean pipes are marked on maps and the such, this is typically unreliable in that the pipes oftentimes are routed in different locations as compared to those on a given map.
Another problem that exacerbates the task of locating a given pipe is the widespread use of non-metallic pipe such as plastic or PVC pipe. Previous methods for locating metallic pipes utilized metal detectors. This is inadequate when considering the use of PVC pipe. Another method for locating pipes is to bury a metal wire such as copper adjacent to the pipe to facilitate later location thereof with metal detectors or cable locators. This, of course, is very expensive and impractical for systems utilizing a large amount of subterranean pipe, such as a sprinkler system. Other applications include pipes located in rivers, lakes and the oceans which are difficult to access with conventional metal detectors.
In view of the above disadvantages, there exists a need for a method and apparatus for economically locating subterranean pipe.